The present invention relates to an improvement in a radar receiver, which when applied to such a receiver can correct the differential error in the detected Off-Boresight Angle (OBA) of a target. This correction is achieved using a closed loop linearization technique which, in combination with correction for known antenna properties, results in improved differential error correction capability as well as substantial elimination of the deterministic errors commonly encountered in radar systems, especially monopulse systems.
Presently known systems use a simplistic technique for differential error correction. This technique comprises correcting the observed OBA of the target with values contained in a static lookup table. The values in the static lookup table are essentially known antenna parameters obtained through pre-calibration which would introduce an error in the observed azimuth angle if not corrected for. These presently known systems however, do not have the ability to correct for deterministic type errors which are introduced into the system as a result of antenna tolerances, construction methods and time and thermal variations introduced by various system components which, especially if such errors are in the same direction of the angular origin of the target signal, introduce a deterministic error in the detected OBA as a function of the current azimuth.
It would therefore be greatly advantageous to provide a system which is not only capable of correcting for differential errors through compensation for known limiting antenna parameters, but which also has the capability of eliminating the deterministic errors introduced by system components as well as time and thermal variations of system components.